Effect of temperature on quantifying glycated (glycosylated) hemoglobin by cation-exchange chromatography

As a consequence of nonideal chromatographic conditions, values for stable glycated hemoglobin (HbA1c) determined by cation-exchange chromatography in a commercial minicolumn system (y) or by "high-performance" liquid chromatography (x) differ markedly, yielding the regression line y = 0.82x + 0.6. With use of the protocol specified by the manufacturer, 20% of the HbA1c peak is not collected in the HbA1c fraction. Increasing the ionic strength of the eluting buffer by increasing the operating temperature to 28 degrees C increases the rate of elution from the minicolumn, making results of the two methods more closely comparable (y = 0.98x - 0.22). Because at a given pH the elution volume is determined primarily by the ionic strength, close limits on the composition of the eluting buffer are set by the temperature-dependence of its ionic strength. At a specified temperature and pH the position of a peak can be judged to within a volume of 1 mL if the conductivity of the eluent does not vary by more than +/- 0.05 mS.     

Photobiomodulation therapy on expression of HSP70 protein and tissue repair in experimental acute Achilles tendinitis

Lasers in Medical Science - The aim of the present study was to investigate the effects of photobiomodulation (PBM) therapy on the expression of heat shock protein 70 (HSP70) and tissue repair in...     

Influence de l'hyperoxie en repos et en effort,sur la mécanique ventilatoire chez les malades souffrant de fibrose pulmonaire

Résumé On a soumis à une épreuve d'effort de 10 minutes au cycloergomètre, 12 sujets sains et 38 malades avec silicose ou tuberculose pulmonaire, forme stabilisée.En repos, en effort et dans la phase de rétablissement, on a calculé les valeurs des paramètres de la mécanique ventilatoire, suivants: le rapport entre la durée de l'expiration et de l'inspiration que les auteurs considèrent comme l'un des plus importants indices dans l'étude de la mécanique ventilatoire, le travail ventilatoire et la compliance pulmonaire, tant dans l'atmosphère habituelle, que dans celle où la concentration de l'oxygène est portée à 98%. On a observé que dans cette dernière atmosphère (98%), la durée de l'expiration augmente, donc le rapport I/E baisse, la valeur du travail ventilatoire diminue (surtout les résistances non-élastiques) et la valeur de la compliance pulmonaire augmente (diminue la pression élastique). Ce fait serait dû à la réadaptation des voies aériennes supérieures et moyennes aux nouvelles conditions favorables crées par l'élévation de la concentration de l'oxygène dans l'air inspiré.     

Elevated frequencies of natural killer T lymphocytes in myasthenia gravis

T lymphocytes are considered to exert a regulatory function in the development of antiacetylcholine receptor antibodies, but no clear T-cell alterations in patients with myasthenia gravis (MG) have yet been found. The authors report a significant increase of recently identified natural killer T lymphocytes expressing T-cell receptor Valpha24. A possible role in disease initiation or maintenance is suggested by the observed strong synthesis of interferon-gamma as well as of interleukin 4.     

Approaches to evaluating the toxicity and carcinogenicity of man-made fibers: summary of a workshop held November 11-13, 1991, Durham, North Carolina.

The Workshop on Approaches to Evaluating the Toxicity and Carcinogenicity of Man-Made Fibers (MMF) was held in Durham, North Carolina, on November 11-13, 1991. The goal of the workshop was to reach a consensus, or to determine the extent to which a consensus existed, in two areas. Participants were asked to identify scientifically sound approaches for evaluating the toxicity and carcinogenicity of man-made fibers based on today's science and to determine research appropriate for study during the next 5 years that can provide an improved scientific basis for future revisions of approaches used to evaluate man-made fiber toxicity and carcinogenicity. During the first day, a series of "state of knowledge" presentations were made to provide all participants with a common data base from which to interact and discuss scientific issues. The workshop participants were assigned to one of four discussion groups, which met separately in three half-day sessions following the first day of presentations. All groups discussed the same topics: exposure assessment, hazard identification, and dose-response information needed to integrate to characterize risk in the first session; approaches to obtaining the needed information in the second session; and recommended approaches and guidelines for evaluating the toxicity and carcinogenicity of MMF and research needs in the third session. The workshop participants reconvened as a whole after each discussion session, and one member from each group reported the group's conclusions. A closure period was also included at the end of the workshop for review and discussion of items that had been considered during the workshop. The primary conclusions reached were the following: -All fiber types capable of depositing in the thorax are not alike in their pathogenic potential. -Only fiber samples with dimensions similar to those to which humans can inhale should be tested. -A complete characterization (i.e., dimensions, fiber number, mass, and aerodynamic diameter) of the fiber aerosol and retained dose is essential. -Appropriate aerosol generation methods must be used for inhalation studies in order to preserve fiber lengths. -A tiered approach to toxicity evaluation is recommended that includes: 1. In vitro screening for durability, surface properties, cytotoxicity, and similar properties, etc; 2. Short-term inhalation or other in vivo studies; 3. That chronic inhalation studies are the "gold standard" (i.e., provide most appropriate data for risk characterization). -The rat is the most appropriate species for inhalation studies. -In chronic inhalation studies, animals should be retained to at least 20% survival after 2-year exposure. -Serial lung burden analyses are an essential component of inhalation studies and are essential for understanding exposure-dose-response relationships. -Studies oriented to understanding mechanisms of toxicity and carcinogenicity are important adjuncts to traditional toxicity studies. -Histopathological analyses of tissues of the respiratory tract represent primary endpoints for evaluating effects of inhaled fibers. Major effects include pulmonary fibrosis, lung tumors, and mesotheliomas. Experimental tissues should be archived for future studies; wherever possible, handling and preservation of tissues should be done in a way that maximizes their future use in mechanistic studies. -Potential human exposures throughout the entire life-cycle of the fiber must be considered and fibrous material for toxicologic studies prepared accordingly. -Intracavity studies are inappropriate for risk characterization but can play a useful screening role in assessing fiber toxicity.(ABSTRACT TRUNCATED AT 400 WORDS)     

Roentgen findings in the full-size abdominal radiograph in occlusion syndromes at the visceral aortic branches (author's transl)]

The acute visceral ischaemia syndrome (which, in typical cases, is caused by embolism or thrombosis of the arteria mesenterica cranialis or, in some cases, by a functional reduction of flow in that vascular area), is usually assigned to the roentgenologist under the heading "acute abdomen" for effecting an abdominal fullsize radiograph. Although this does not allow safe diagnosis and differential diagnosis, it does provide valuable pointers in quite a number of cases. One of the most specific symptoms is the so-called flexure cut-off symptom consisting of a pronounced accumulation of gas (wind) from the caecum to the left flexure. a typical case and one each similar case in a chronic visceral triple occlusion and a polycythaemia, are demonstrated. The mandatory diagnostic consequence of this symptom is immediate aorto-arteriography unless a functional cause is evident and can be successfully treated by conservative measures.